Surface grinder or related unit



March 17, 1970 F. w. FISCHER 3,500,583

SURFACE GRINDER OR RELATED UNIT Filed Dec. 5. 1966 2 Sheets-Sheet 1 "'1'FIG.I

INVENTOR. "FRED W. FISCHER BY r ATTORNEYS March 17, 1970 F. w. FISCHERSURFACE GRINDER OR RELATED UNIT 2 Sheets-Sheet 2 Filed Dec. 5, 1966 illINVENTOR. FRED W. FISCHER Illllll llllllllllllH I I l l I FIG.4

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ATTORNEYS United States Patent 3,500,588 SURFACE GRINDER OR RELATED UNITFred W. Fischer, 1450 Silver Bell Road, Rochester, Mich. 48063 FiledDec. 5, 1966, Ser. No. 599,108 Int. Cl. B24b 7/10 U.S. Cl. 51119 12Claims ABSTRACT OF THE DISCLOSURE A power spindle rotatively drives atubular housing encircling the spindle, the drive being through auniversal ball and socket connection; and the housing carries a cuttingtool. An adjustable wedge-type slide plate in turn cases the rotatinghousing to have a continual oscillatory motion eccentric of the spindleaxis, thus compounding this action at the tool with a spindle-derivedrotative action. A separate power source drives the housing for theoscillatory motion; and the slide plate has cam means to adjust it andthe path of the oscillatory motion during the operation of the tool.

The present invention relates to a unit to perform an improved surfacegrinding or related type of material removing or treating operation onworkpieces. More particularly, the unit of the invention is one which isintended to be applied as an adapter to a known type of surface grinderhead (although its application to equipment for the milling, polishingetc., of objects is also contemplated), and thereby produce an improved,compounded and oscillatory action of the rotary wheel of the head on theworkpiece. A typical head to which the improved unit of the inventionmay be readily applied is the Model No. 24 grinder of Mattison MachineWorks of Rockford, Ill.

This type of grinder equipment features a so-called quick tilt head forthe successive performance of rough and finish grinding cuts; and thearrangement is such that for initial rough grind the power spindle ofthe wheel is tilted a very slight amount relative to the vertical (in anupright spindle machine), thus to produce a departure of the grindingsurface from the horizontal amounting to, say, 0.010 inch. In the final,finish cutting phase, the wheel is restored to true horizontalparallelism with the work surface being ground.

The purpose of the quick tilt arrangement is to get rid of metal orother particles removed from the workpiece in the rough cut, as well asbroken down grit, while the cut is being made. It is, however,characteristic of this tilt type of equipment that the wheel attacks theworkpiece, as the latter is held by a magnetic or like rotary chuck,solely at a peripheral wheel edge at the commencement of the cut, i.e.,adjacent the center of the chuck, the Wheel progressively taking flushsurface engagement with the workpiece surface (in a radially outwardsense) as material removal proceeds. The result is that the rough-groundsurface has a slightly dished or concavely coned shape.

On the other hand, during the finish grinding phase, the attack of thewheel on the rough-ground surface is progressively in the oppositedirection, i.e., from the rim of its dish toward the center of thechuck, until the wheel surface again comes in flush parallelism with theultimately ground finish surface. The result is that, although theconventional tilt-head feature is effective in dispersing metalparticles and grit during rough and finish passes, the entire abrasivesurface of the grinding wheel acts on the workpiece during only aportion of the elapsed time of the respective rough and finish grindingoperation. This is inefficient, production-wise and, moreover, requiresthe expenditure of considerable power to Patented Mar. 17, 1970 ICCproduce the finished product, as well as at a slower rate. For example,heads of a rating of HP are in common use. Still further, it is usuallynecessary to employ wheels of as much as five different hardnesses inthe grinding of stock of different hardness, i.e., a soft wheel for ahard workpiece, and vice versa, within the work hardness range.

It is therefore an object of the present invention to provide animproved unit applicable to a conventional grinding or related materialremoving or treating head, which may be either a tilt head type or not,in which the wheel (and it may with comparable advantage be either asegmented or a continuous ring one), has a compounded oscillatory motioninengagement with the workpiece surface throughout the operation. It maybe operated under heavy pressure for a fast cut, yet is not subject toobjectionable heating, and gets rid of metal particles and fracturedgrit in the desired manner. It of course follows that the amount ofmetal or other material that may be removed in a grinding phase of givenduration is multiplied; a much lesser horse power input is required.Rough and finish grinding may be performed on metals of the usualhardness range by operating in as little as two grades of wheelhardness.

Further in accordance with the invention, the grinding or otheroperating tool, as mounted generally concentrically of and driven athigh speed by the power spindle of the conventional head, isnevertheless given an independent rotary motion at less speed by theunit, and about an axis a bit eccentric of the axis of the powerspindle. Thus, since the lateral displacement of the eccentricityrelative to the last named axis is continually changing, there resultsthe mentioned oscillatory action of the tool on the workpiece surface.The action physically involves a slide-modified motion of an oscillatoryhousing on which the operating wheel is carried, which motion resemblesthat of a wobble plate or swash plate.

In still further accordance with the invention, the improved unit hasmeans to adjust the extent of the eccentricity during the grindingoperation, thus enabling the extent of throw of theoscillation-imparting component to be quickly varied, should need arise.

Another object of the invention, in a more specific aspect, is toprovide a unit of the type described, in which the mount afforded by theunit for the grinding wheel includes a slide capable of a rectilinearadjusting movement transversely of the spindle axis. The adjustment isof small extent on a slide guiding and driving plate, which plate has adrive connection to an independent low speed power source. On the otherhand, a motion-modifying connection of the slide to the wheel assemblyis made through the agency of an elongated oscillatory housing andspecial universal means drivingly connecting the housing to the wheel.

Thus the guide and drive assembly, as rotated at slow speed from asource independent of the spindle drive, nuta'tes the slideeccentrically of the spindle axis, in turn continuously tilting andvarying the direction of eccentricity of the oscillatory housingrelative to the spindle axis to produce the compounded eflect referredto.

In further accordance with the invention, the special connection of theoscillatory housing to the spindle of the head is of a ball and sockettype to accommodate the tilt and oscillatory shift of the housing andwheel driven thereby. The eccentrically disposed slide is also connectedto the housing through special bearing means to accommodate the latterstilt in oscillation, and the housing has still further special bearingmeans journalling the same in a fixed housing part of the unit for thesame purpose. There is continuous contact ofthe wheel with the workpieceregardless of the continuously changing inclination of the oscillatoryhousing axis to the spindle axis, which inclination or tilting arisesfrom the essentric rotation of the housing-mounting slide relative tothe spindle axis.

Pursuant to the invention the connection of a driving ball, drivinglyconnected to the power spindle, to the oscillatory housing and operatingwheel is a key-like one which will permit the desired ball and socketaction, being preferably in the form of an annular series of smallballs, each drivingly received in an arcuate recess in the periphery ofthe main driving ball, at a diameter thereof, and drivingly connectedthrough the socket to the oscillatory housing.

A further specific object of the invention is to provide a unit in whichthe eccentricity of the slide may be readily and accurately adjustedthrough the agency of inclined wedge surfaces on opposite outer ends ofthe slide, which surfaces matingly engage correspondingly inclined wedgesurfaces of a special slide adjusting ring. This ring is rotativelydriven, along with the slide, by the guide and drive plate for thelatter; and provision is" made to vary the relative position of therespective wedge surfaces in a direction paralleling the rotative axis,by shifting the adjusting ring axially, with the result that the slideis wedged or cammed along its guide and drive plate, in one direction orother at 90 to the axis. This provides a simple means for accuratelyadjusting the eccentricity of the slide and oscillatory housing axisrelative to the spindle axis for the purpose described above.

"In further specific accordance with the invention the means foreffecting the slide adjustment is such that it may be operated readilyfrom an external point and while the grinding or other finishing ortreating operation proceeds. Such means takes the form of an externallythreaded, rotatively fixed but axially shiftable annular screw member oflarge diameter, which screw member is in threaded engagement on itsperiphery with ari annular rotatable, internally threaded elevating anddepressing nut member. Annular rack and pinion-type means enable thelast named member to be rotated during the work finishing operation,thereby raising or lowering the screw member; and the latter isoperatively connected to the slide adjusting ring to effect the desiredslide adjusting wedge action as the result of a vertical shift of theadjusting ring by the elevating and depressing. screw member.

In still further accordance with the invention, the slide guide anddrive plate, as slowly rotated on an axis eccentric of that of thespindle by a power source independent of the main spindle power inputsource, is drivingly connected to said independent source by a rack andpinion-type connection. The source is a variable speed motor ofrelatively small power rating, since the load is small.

The foregoing, as well as other objects, will become more apparent asthis description proceeds, especially when considered in connection withthe accompanying drawings illustrating the invention, wherein:

FIG. 1 is a fragmentary view in vertical section, as in the plane 1.1 ofFIG. 2, through the rotative axes oft he improved unit and the powerspindle of a conventional grinder head to which the unit is applied asan adapter, the view generally indicating in solid and dotted lines'twopositions of adjustment of an elevating and depressing ring of the unitin producing a wedging rectilinear adjustment of a slide rotativelydriven by a slide guide'and drive plate, thus to adjust eccentricity asmen- ;ioned :above;

FIG. 2 is a fragmentary view, partially broken away, n horizontalsection on line 2-2 of FIG. 1;

FIG. 3 is a view in vertical section of the elevating rnd depressingring above referred to, as on Section line l-3 of FIG. 2; and

FIG. 4 is a view in section similar to FIG. 3 of the assembled slide andits guide and drive plate.

Referring to FIG. 1, a portion of a Model 24 Mattison grinder head ofthe quick-tilt type is generally designated by the reference numeral 10.The parts appearing in that figure include a motor housing 11 having anannular bottom boss 12, in a bore of which a lower bearing cartridge 13encasing lower spindle ball bearings 14 is concentrically received.These rotatively journal the lower end of an elongated drive spindle 16,which will be operated at high speed by a motor (not shown) of, say, 75HP rating.

The reference numeral 18 generally designates an improved head adapteror conversion unit of the present invention, which will presently bedescribed in detail; and the reference numeral 20 generally designates atypical grinding wheel assembly of unit 18. This assembly is shown asbeing constituted by a continuous cylindrical abrasive wheel 21 suitablymounted to an annular steel backing ring 22. Ring 22 is received in anannular recess 23 of equal dimensions about the periphery of the bottomof a special mounting body 24 of unit 18. A workpiece W is shown asbeing mounted on the top of a rotary magnetic chuck C; the axis ofrotation is shown at A. It is, of course, to be understood that othertypes of work holder may be employed, also that the wheel 21 may be asegmented or other type known to the art.

In accordance with the invention, the wheel body 24 is formed to providea center quasi-spherical recess or seat 25 of substantial diameter andcoaxial with wheel assembly 20; and this recess matingly receives thebottom half 26 of a socket 27. Socket half 26 is drivingly connectedappropriately in a fired manner to wheel body 24, and presents aninternal and upwardly facing, quasispherical socket surface 28.

The upper half of the socket 27 is the form of an integral formation 31at the bottom of an axially elongated and otherwise cylindricaloscillatory housing 32 of substantial diameter. Housing 32 surrounds thespindle 16 with substantial radial clearance at 33 and serves importantfunctions other than of affording the formation 31, as will appear.

The last named formation has a quasi-spherical internal and downwardlyopening socket surface 35 of the same radius as bottom socket surface28, so that when the oscillatory housing 32 and bottom socket member 26(which in effect completes the housing) are secured in axially aligned,face to face engagement with one another, as by a series of screws 36,the surfaces 28 and 35 constitute a universal joint to receive aquasi-spherical ball 38 of the same diameter. Ball 38 is conically boredfrom above and counterbored at its bottom to matingly receive the usualconical nose of spindle 16, as well as a bolt 39, which bolt threadsupward into the spindle nose to lock ball 38 to the bottom of thelatter. A driving connection between the spindle and ball is provided ata key 40 on the former; the ball is in turn drivingly connected to thesocket 27, as constituted by members 26 and 31, through the agency ofseveral small antifriction bearing balls 41, which permit a swivelaction of oscillatory housing 32 of drive ball 38.

Thus, each bearing ball 41 is received in part in an upright arcuategroove 42 formed in ball 38 at a horizontal diameter plane thereof, andin part in a semispherical seat 43 formed at the meeting line of socketmembers 26 and 31. Accordingly, the ball and socket members afford auniversal driving connection between spindle 16 and the wheel assembly20 for the primary rotative drive of the latter, the drive transmittingballs 41 allowing a slight swivel of the wheel assembly relative to theaxis of spindle 16. This is important in relation to the eccentricallydriven motion in operation of the oscillatory housing.

The wheel mounting body 24 and socket member 26 are centrally aperturedat 45, coaxially of the locking bolt 39, for convenient access to thelatter. It is of course contemplated that the unit 18 of the inventionis of equal utility and merit when applied to a head whose spindleoperates on a horizontal or other than vertical axis.

The unit 18 includes a fixed housing 47 of considerable diameter whichis internally belled at its lower portion, the oscillatory housing 32extending upwardly through a circular throat 48 of housing 47. Thelower, skirt-like portion of that housing 47 receives the outer race ofa special ball bearing 50 of quite large diameter; the inner race ofthis bearing being fixedly mounted to the universal socket structure 26,31 at the diametral zone at which its two component portions meet. Ballbearing 50 is, as a significant feature of the invention, one whose racesurfaces 51 are slightly arcuate and concentric, thus to permit a slightswiveling tilt of oscillatory housing 32 relative to the spindle axis,just as the driving balls 41 permit a tilt of that housing and wheelassembly 20 relative to the same axis. This ties in with the eccentricdrive of housing 32.

Reference being had to FIGS. 2, 3 and 4 in conjunction with FIG. 1, theupper cylindrical end of the oscillatory housing has a splined or likefixed driving connection 53 at its top with the inner race of a secondball bearing 54 of somewhat smaller diameter than the lower bearing 50;and bearing 54 also has slightly arcuate and concentric race surfaces 55which will permit a slight tilt of oscillatory housing 32 relative tothe axis of spindle 16, for the eccentricity-accommodating actionmentioned above.

The outer race 56 of ball bearing 54 is fixedly secured in a cylindricalopening of an eccentricity adjusting slide or slide plate 57 which, asbest shown in FIGS. 2 and 4, has diametrically opposed outwardly convexends of corresponding arcuate extent. These ends are formed to provideparallel wedge surfaces 59 and 60 about their respective arcuatelengths; and the wedge surfaces 59, 60 are subtended by parallel uprightand rectilinear side surfaces 61, 62 of slide 57. For the purpose ofconvenience, as viewed in FIG. 4, wedge surface 59 may be considered tobe undercut or downwardly relieved and the opposite wedge surface 60 tohe beveled or upwardly relieved. These surfaces 59 and 60 functionimportantly in the adjustment of the axis of eccentricity of oscillatoryhousing 32 in action, hence of the various drive parts and wheelassembly 20 which are carried thereby.

The slide 57, and the ball bearing 54 through which it is operativelyspline-connected to the top of oscillatory housing 32, are slidablyguided for their slight rectilinear adjusting movement on the top of aspecial circular slide guide and drive plate, generally designated bythe reference numeral 64. This plate has an integral annular, downwardlyprojecting flange or shoulder 65 surrounding a central bore 66 which hassubstantial radially outward clearance at 67 from oscillatory sleeve 32.

Flange 65 slides rotatively on a top surface of the fixed housing 47surrounding the latters bore 66; and ball bearings 68 outwardly journalthe plate flange 65 for this rotation, acting between the latter and anupright cylindrical wall 69 of housing 47. Provision is made outwardlyof this wall for the independent rotative drive of plate 64 atrelatively low speed, as will be later described.

Referring particularly now to FIGS. 2 and 3 in conjunction with FIG. 1,the plate 64 is provided witlia wide, upright-walled recess ofsubstantial axial depth across its upper surface, the recess beingdefined by parallel side walls 71 (FIG. 2); and the sides 61 of slide 57are guided for rectilinear eccentricity adjusting movement between thesewalls, with the slide also having a rotative drive from the recess walls71 at a relatively slow speed as compared with that of the spindle 16and wheel assembly 20.

Referring to FIG. 1, the fixed housing 47 of unit 18 includes an annularhorizontal and radially outwardly extending flange formation 73 whichhas an annular upright outer confining rim or shoulder 74. A cover plate75 of relatively large diameter is secured downwardly upon this shoulderby a series of set screws 76; and cover plate 75 confines the slide 57and special bearing 56 from above, as well as other adjusting componentsto be described, while permitting free rectilinear adjusting shift ofthe slide. An adapter plate 78, to which cover 75 is connected by screws79, is in turn upwardly connected by screws or bolts 80 to the bottom ofthe annular boss 12 of the housing 11 of head 10.

Slide 57 is operated directly in its adjusting action by a flatadjusting ring of large diameter, generally designated 82, of a specialkind, which is best illustrated in FIG. 3. It is cylindrical on itsexterior, save for the :presence of a small outwardly projecting annularflange 83; 'and it is also generally cylindrical on its interior surface84, save for the presence of inclined wedge surfaces 85, 86 indiametrically opposite end zones thereof which are, like slide wedgesurfaces 59, 60, also of substantial arcuate extent. Inclined surfaces85 of slide 57 hence may be considered to be downwardly and inwardlybeveled, while the opposite surface 86 has a similar mating coactionwith the slide wedge surface 60', hence may be considered to bedownwardly undercut. At opposite arcuate ends of the wedge surfaces 85,86 the same meet opposite upright end walls 87 in the bore of adjustingring 82; and the extremities of opposite sides 61 0f slide 57 arereceived within and guided by these parallel upright wall components 87,just as the remainder of the slide sides are guided between the recesswalls 71 of guide and drive plate 64.

Thus, as guided for rectilinear adjusting action by walls 71 and 87,with its wedge surfaces 59, 60; respectively engaging the surfaces 85,86 of slide guide and drive plate 64, the slide 57 is also rotativelydriven on an upright axis by those walls.

As indicated above, the wedging adjustment is made as the result ofrelative movement of the pairs of adjusting ring and slide wedgesurfaces 59, 85 and 60, 86 in a direction parallel to the axis ofspindle 16. More specifically, since the slide 57 is restrained by coverplate 75 against vertical movement, it is the adjusting ring 82 which isshifted in the axial direction; and this is done through the agency ofthe integral annular side flange 83 of the ring.

As best shown in FIG. 1, a pair of large diameter annular and threadedlyengaging adjusting screw and nut members 88, 89, respectively, coactwith ring 82 for the purpose, the screw member 88 being externallythreaded for coaction with internal threading of the nut member 89 at90. Member 88, which is held against rotation in the adjustment (member89 being rotated by means to be described), has an internal annular,flange-like shoulder 91; and the side flange 83 of adjusting ring 82rests and runs on shoulder 91. An annular retaining ring 93 is securedfrom above onto said adjusting screw member 88, acting to restrainflange 83 from above, but with a running clearance relative tothe later.

As best shown at the right of FIG. 1 (reference also being had to FIG.4), the adjusting screw member 88 is restrained against rotation on theflange 73 of fixed housing 47, as by a series of axially extendingdowels 95. These extend through bores in member 89 and into the fixedflange 73 and cover plate 75.

Adjusting ring 88 is of the nature of a special ring gear, in that ithas a circumferential series of gear or rack teeth 96 formed on andabout its bottom. These teeth are meshingly engaged by a. pinion 97fixed on a small, radially extending and rotatable shaft 99, which shaftextends outwardly of fixed housing shoulder 74 through a bushing 100 inthe flange 73 of which the shoulder is a part. Shaft 99 has a hand wheel101 secured on its outer end.

Accordingly, a rotation of hand wheel 101 in one direction or anothercauses a corresponding rotation of adjusting nut member 89, accompaniedby axial shift of the rotatively fixed annular adjusting screw member88; and the adjusting ring 82 is correspondingly elevated or lowered.There is an attendant wedging adjustment of slide 57, horizontally inone direction or another, to vary the eccentricity of oscillatoryhousing 32 at its cylindrical bore space 33 relative to the axis ofspindle 16; and as the latter drives wheel assembly 20 at high speedthrough the agency of ball 38, the constantly changing slideeccentricity (in relation to'the spindle axis) is superposed as areciprocatory and nutative component on the normal rotation of housing32 and wheel assembly 20, resulting in the desired oscillatory action ofthe latter.

The motion of oscillatory housing 32 resembles that of a wobble plate orswash plate; and as indicated above, the special bearing provisionsassociated with oscillatory housing at ball 38, socket 27 and bearings41, 50 and 54 permit the tilting shift of housing 32 relative to spindle16.

It is to be seen that the adjusting of slide and housing eccentricitymay be made while grinding is taking place, .due to the use of theadjusting ring, screw and-nut members 82, 88, 89, respectively.

The compounded oscillatory action of wheel assembly 20 of courseinvolves importantly the independent rotative drive of the slide 57 byplate 64 at the top recess of the latter, and the attendant rotativedrive of adjusting ring 82 within rotatively fixed adjusting screwmember 88. To this end, the plate 64 is equipped at its bottom and aboutits circumference with a series of downwardly extending rack or gearteeth 104 (FIGS. 1 and 4), which are meshingly engaged by a small pinion105 located just radially outwardly of upright wall 69 of fixed housing47 and the radial bearings 68. Pinion 105 is fixed on a radiallyelongated shaft or spindle 106 which is journaled in a bushing 107 inthe fixed housing flange 74; and shaft 106 is driven independently ofthe drive or power spindle 16, and at much lower speed than the latter,as by a variable DC motor (not shown) rated from 5 to 50 rpm.

Accordingly, with the slide guide and drive plate 64 so driven, and sodriving the slide 57, the eccentricity of oscillatory housing 32, asconnected by bearing 54 to the slide, is continuously altered at thehousing-to-spindle clearance space 33 (FIG. 1) with resultant productionof the'improved oscillatory action contemplated by the invention. Axialmovement of adjusting ring 82 is accommodated in an annular bottomrecess 109 in cover plate 75. a

It is seen from the above that the invention affords a unit capable ofbeing readily applied to a conventional type of grinder or other poweredoperating unit, as a conversion or adapter device for such a head, whichunit substantially and significantly modifies the working action of anoperating wheel assembly of the unit on a workpiece. A compoundedoscillatory characteristic is imparted to the wheel assembly which is ofgreat utility in improving the grinding or other action. That is, thewheel is kept continuously in engagement with the workpiece, in anaction which sweeps away metal particles and grit dislodged from thewheel. Increased operating pressures may be employed, but withoutcreating objectionable heat. The duration of the grinding operation isdiminished; and these advantages are obtained with a significantlydecreased input of power at the spindle of the head, as compared withwhat is commonly employed in known type equipment.

What is claimed is:

1. In a grinding or related unit which is adapted to be driven inoperation by a grinder or related type power head to operate upon a flatsurface of a work-piece, said units having means rotatively driven by anoutput member of the head and supporting an operating tool member toingage the latter wi h said workpiece surface at the plane of saidsurface; the improvement in accordance with which said unit comprisesrelatively driven means to compound the rotation of said output member,as applied to said tool member, with a generally oscillatory, onbitallytraveling motion of the latte-r in its said engagement with theworkpiece at said surface plane, and means operatable during theoperation of said unit to adjust the orbital path of said oscillatorymotion.

2. The unit of claim 1, in which said motion compounding means comprisesmeans drivingly connecting said output and tool members and acting toimpose an eccentric component of limited throw upon the rotary motion ofthe output member to produce said oscillatory motion of the tool member.

3. The unit of claim 1, in which said motion compounding means comprisesmeans drivingly connecting said output and tool members and acting toimpose an cecentric component of limited throw upon the rotary motion ofthe output member to produce said oscillatory motion of the tool member,and means to produce said eccentric component from a source independentof the power drive of said head.

4. The uni-t of claim 3, said last named means comprising means toadjust the extent of said eccentric throw.

5. Ina grinding or related unit which is adapted to be driven inoperation by a grinder or related type power head, said unit havingmeans rotatively driven by an out- .put member of the head andsupporting an operating tool member to engage the latter with aworkpiece; the improvement in accordance with which said unit comprisesmeans to compound the rotation of said output member, as applied to saidtool member, with a gene-rally oscillatory motion of the latter in itssaid engagement with the workpiece, and means operable during theoperation of said unit to adjust the path of said oscillatory motion,said motion compounding means comprising means drivingly connecting saidoutput and tool members and acting to impose an eccentric component oflimited throw upon the rotary motion of the output member to producesaid oscillatory motion of the tool member, said means imposing saideccentric component comprising a slide and means guiding said slide fora rectilinear adjustment at to the axis of rotation of said outputmember of the head, said guide means and slide having means driving thesame on an axis eccentriepf that of said rotative output member.

6. The unit of claim 5, in which said adjusting means comprises coactingwedge surfaces on said slide and its gu de means to variabley shift theslide transversely of said eccentric axis upon relative movement of thewedge sfiiffaces in a direction normal to that of the variable s Y t.

7. The unit of claim 5, in which said throw adjusting means comprisescoacting wedge surfaces on said slide and its guide means to variablyshift the slide transversely of said eccentric axis upon relativemovement of the wedge surfaces in a direction normal to that of thevariable shift, and means to effect sa-id relative movement of the wedgesurfaces during said workpiece engaging motion of the tool member.

8. The unit of claim -1, in which said adjusting means comprisescoacting movable members, one of which engages a part of said mechanismwhich supports the tool member to make the adjustment and the other ofwhich operates said one member, and means to actuate said other memberfrom the exterior of the unit.

-9. The combination with a grinder or related type power head ofmechanism rotatively driven by an output member of said head andsupporting an operating tool member to operate upon a flat surface of aworkpiece at the plane of said surface, said mechanism comprisingrotatively driven means to compound the rotation of said output member,as imparted to the tool member through the mechanism, with a generallyoscillatory, orbitally traveling moiion of the latter in its engagementwith the workpiece at said surface plane, and means operable during theoperation of said tool member to adjust the orbital path of saidoscillatory motion.

10. The combination of claim 9, in which said adjusting means comprisescoacting movable members, one of which engages a part of said mechanismwhich supports the tool member to make the adjustment and the other ofwhich operates said one member, and means to actuate said other memberfrom the exterior of the unit.

11. The combination with a grinder or related type power head ofmechanism rotatively driven by an output member of said head andsupporting an operating tool member, said mechanism comprising means tocompound the rotation of said output member, as imparted to the toolmember through the mechanism, with a generally oscillatory motion of thelatter in its engagement with a workpiece, and means operable during theOperation of said tool member to adjust the path of said oscillatorymotion, said compounding means comprising a slide and means guiding saidslide for a rectilinear adjustment at 90 to the axis of rotation of saidoutput member of the head, said guide means and slide having meansdriving the same on an axis eccentric of that of said rotative outputmember.

12. The combination of claim 11, in which said adjusting means comprisescoacting wedge surf-aces on said slide and its guide means to variablyshift the slide transverse-1y of said eccentric axis upon relativemovement of the wedge surfaces in a direction normal to that of thevariable shift.

References Cited UNITED STATES PATENTS 1,343,050 6/ 1920 Goodwin 51-1-202,105,634 1/1938 Brendel 5l119 X 3,212,373 10/1965 Basso 2796 X2,975,565 3/196'1 Phillips 51--124 HAROLD D. WHITEHEAD, Primary ExaminerUS. Cl. X.R. 5l134.5

